import java.net.InetAddress;
import java.net.NetworkInterface;
import java.util.Enumeration;
import java.util.regex.Pattern;

/**
 * author:wzq
 * date:16-2-9
 * project:getIp
 * description: TODO
 */


public class GetIp3 {


    private static final String LOCALHOST = "127.0.0.1";
    private static final String ANYHOST = "0.0.0.0";
    private static final Pattern IP_PATTERN = Pattern.compile("\\d{1,3}(\\.\\d{1,3}){3,5}$");

    /**
     * 遍历本地网卡，返回第一个合理的IP。
     *
     * @return 本地网卡IP
     */
    private static InetAddress getLocalAddress0() {
        InetAddress localAddress = null;
        try {
            localAddress = InetAddress.getLocalHost();
            if (isValidAddress(localAddress)) {
                return localAddress;
            }
        } catch (Throwable e) {
        }
        try {
            Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
            if (interfaces != null) {
                while (interfaces.hasMoreElements()) {
                    try {
                        NetworkInterface network = interfaces.nextElement();
                        Enumeration<InetAddress> addresses = network.getInetAddresses();
                        if (addresses != null) {
                            while (addresses.hasMoreElements()) {
                                try {
                                    InetAddress address = addresses.nextElement();
                                    if (isValidAddress(address)) {
                                        return address;
                                    }
                                } catch (Throwable e) {
                                }
                            }
                        }
                    } catch (Throwable e) {
                    }
                }
            }
        } catch (Throwable e) {
        }
        return localAddress;
    }

    private static boolean isValidAddress(InetAddress address) {
        if (address != null) {
            String hostIp = address.getHostAddress();
            if (hostIp.startsWith("10.") || hostIp.startsWith("172.")) {
                return true;
            }
        }

        //isLoopbackAddress:127.*,isSiteLocalAddress:局域网ip,isLinkLocalAddress:169.254.*,isMulticastAddress:224.0.0.0 ~ 239.255.255.255
        if (address == null || address.isLoopbackAddress() || address.isSiteLocalAddress() || address.isLinkLocalAddress()
                || address.isMulticastAddress() || isSpecialIp(address.getHostAddress())) {
            return false;
        }
        String name = address.getHostAddress();
        return (name != null && !ANYHOST.equals(name) && !LOCALHOST.equals(name) && IP_PATTERN.matcher(name).matches());
    }

    private static boolean isSpecialIp(String ip) {
        if (ip.contains(":")) return true;
        if (ip.equals("255.255.255.255")) return true;
        return false;
    }

    public static void main(String[] args) {
        InetAddress addr = getLocalAddress0();
        System.out.println("select: " + addr);
    }
}